Composite Phosphor Particles for Single-Detector Authentication
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Solution Overview
Problem
Conventional phosphor compositions have limited capabilities in differentiating between tagged articles, requiring multiple detectors to distinguish different wavelengths of emitted radiation, which is inefficient and impractical for certain security applications.
Innovation Solution
A particulate composition comprising multiple crystalline or glass phases with host lattices and dopants sensitive to electromagnetic radiation, producing distinct emission spectra, decay rates, and absorbance characteristics when exposed to the same energy, allowing for varied outputs by adjusting the relative phase ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If different phosphor compositions emitting different wavelengths are used to differentiate tagged articles, then the differentiation capability is improved, but the device complexity increases due to requiring multiple detectors
Solution Approach 1:
The patent changes the parameter of the phosphor composition by incorporating multiple crystalline phases (e.g., cubic and hexagonal modifications of CaAlSiN3) within a single particle. Each phase emits at different wavelengths when excited, allowing a single detector to read multiple wavelength responses and differentiate between various phosphor compositions used on different tagged articles.
Solution Approach 2:
The patent uses composite phosphor particles containing multiple crystalline phases (e.g., CaAlSiN3 with different modifications, or combinations like CaAlSiN3 and Sr2Si5N8) doped with various activators (Eu2+, Mn2+, etc.). This composite structure enables single particles to produce multiple emission wavelengths, reducing the need for multiple detectors while maintaining differentiation capability.
2Adaptability or versatility
If multiple detectors are used to read different wavelengths from different phosphor compositions, then the differentiation capability is improved, but the ease of operation deteriorates
Solution Approach 1:
The patent modifies the phosphor composition parameters by creating particles with multiple crystalline phases that emit at different wavelengths. A single detector can then read these multiple wavelength responses, simplifying the authentication process to a single detection step while maintaining the ability to differentiate between various phosphor compositions applied to different articles.
3Device complexity
If a single phosphor composition is used for authentication, then the device complexity is reduced, but the differentiation capability deteriorates
Solution Approach 1:
The patent changes the internal structure parameter of the phosphor by incorporating multiple crystalline phases within single particles. This allows a single simplified detector to read multiple wavelength emissions from different phases, maintaining differentiation capability while reducing device complexity.
Solution Approach 2:
The patent creates universal phosphor particles that perform multiple functions simultaneously - each particle contains multiple crystalline phases that emit at different wavelengths, enabling a single detector to gather multiple authentication signals from a single phosphor composition, thus simplifying the monitoring system while maintaining versatility.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables efficient authentication and differentiation of articles by producing unique responses to excitation radiation, reducing the need for multiple detectors and enhancing security features in applications like banknotes and documents.
Implementation Method 1
Phosphors are compositions that are capable of emitting useful quantities of radiation in the visible, infrared and/or ultraviolet spectrums upon excitation of the phosphor compound by an external energy source
Implementation Method 2
the different phases emit radiation having different decay rates on exposure to photons of the same energy
Data Source
Figure 1a~2d
Figure 3a~3f
Figure 4a~5f
AI summary
A particulate composition comprises a plurality of particles wherein at least one of the particles comprises at least two different crystalline and/or glass phases, each phase comprising a host lattice and a dopant sensitive to electromagnetic radiation. The different phases simultaneously produce different responses on exposure to photons of the same energy, whereby the output from the particulate composition when exposed to said photons is the sum of the responses from the different phases.